The Hegsted Equation has been used extensively to predict changes in plasma cholesterol in response to changes in the saturated fat and cholesterol composition of the diet. While the equation was developed for Caucasians, research based on population survey data suggests that it may not accurately predict blood cholesterol responses to dietary fat changes in Japanese individuals. The cholesterol response to dietary fat alterations was much greater than predicted via this equation in Japanese. No related data is available for Hispanics. Given the increased mortality from cardiovascular disease (CVD) in Japan over the last decade, identification of potential risk factors, such as a hypercholesterolemic response to dietary saturated fat and cholesterol intake, in this ethnic group would be important in designing intervention and prevention programs aimed at reducing CVD risk in high risk individuals. This study is designed to determine whether Caucasian, Hispanic, and Japanese American men differ in their lipid responsiveness to changes in dietary saturated fat and cholesterol and whether the Hegsted Equation can accurately predict blood cholesterol response to dietary fat modification in these three ethnic groups.